


heaven's grown cold

by AwakeAndAliveSpartan



Category: Ao no Exorcist | Blue Exorcist
Genre: Angst, Brother v. Brother, Demon! Yukio, Gen
Language: English
Status: Completed
Published: 2018-09-30
Updated: 2018-09-30
Packaged: 2019-07-20 12:53:05
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 1,554
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16137644
Author URL: https://archiveofourown.org/users/AwakeAndAliveSpartan/pseuds/AwakeAndAliveSpartan
Summary: Rin finds that Yukio's finally gotten the power he's always wanted. But at what cost?





	heaven's grown cold

“I don’t understand. Why does the Illuminati even want this demon anyways? It’s already hard to deal with. And why send us after something that the Illuminati wants?”

Konekomaru pursed his lips, “It’s what Mephisto wanted from us.” he answered, looking back towards the the hovering demon, who of which looked like a shriveled up voodoo corpse. “But, again, that’s a sage. Kin of Azazel. Super rare and rumored to possess the power of immortality. That’s probably what Lucifer wants, right? Mephisto  _ did  _ say that he was looking for a new body. Why not make it immortal as well?”

Suguro nodded slightly, remembering what he and Lightning had uncovered about Section 13 and the elixirs. Lucifer  _ did  _ want a way of making a host immortal so he didn’t have to worry about the body decaying on him. He just wondered why it took the demon king so long to go after a sage. But, it all did make sense in the end. But why put the Exwires up against the Illuminati’s forces?

“Can we just stab it or something?” Rin asked, scratching the back of his head, ruffling his snow white hair. “Before the Illuminati gets their hands on it.”

Konekomaru shook his head, “The demon’s immortal, Rin. I don’t think that stabbing it will do anything. Even with your flames.” he stated in response. “It may look like a corpse, but it’s supposed to have a wickedly fast healing ability. I think it’s best to restrain it and bring it in. I don’t think it’s much of a fighter, if I recall correctly. Perhaps Bon and I can recite different restraining spells. Or Shiemi can restrain it with Nee’s vines. I don’t think that it’ll take much.”

“Where do we start?” Suguro asked, looking over to Konekomaru. “I know a few spells, but I don’t know if they work on Azazel’s kin.”

The boy shrugged, “I don’t know, but we can try. We’ll have to do this while the others try to hold the Illuminati off. They’re not here for some reason.” he explained. “Maybe we’ve got enough time to do it.” He looked over to Izumo and Shiemi, “Can you two stay with Rin?”

Shiemi nodded, “Yeah!” she answered, going over to Rin. “Should I have Nee make a barrier or something around us? That might delay them once they do happen to get here.”

Izumo pulled out her summoning papers for Uke and Mike with a huff, “That might work. I just want to get this over with before they get here.”

Rin marched forward towards the demon, who slowly turned and blinked at him, “I don’t think he’s violent.” he announced. “So not a bad demon, then?” The half-demon slowly began towards the demon once more, only to be knocked back as a wall of fire erupted between him and the demon.

“Rin!” Shiemi cried, running over to him. “Are you okay? That came out of nowhere and-”

“Blue flames….”

Shiemi froze, looking up from Rin to see Suguro frozen in terror staring at the wall of flames, which happened to be blue as the sky above them. “Wait, what?”

Rin shook his head, pulling himself off of the ground, “That’s… That’s not me.” he stated, checking to see whether or not there were flames burning off of him. “Even with Kurikara broken. It’s not me.”

He looked towards the blue wall of flames, seeing them start to die away, revealing a hulking figure looming over the sage demon. His eyes widened as something pulled at his heart. “No….” he mouthed. “No.”

“What the hell is that?!” Suguro yelled. “I’ve  _ never  _ seen a demon like that! And why the hell does it have blue flames?”

The demon turned around and looked at them, something akin to recognition in its glowing eyes. It stood at least seven feet tall and was slender with muscle. Its scale-like skin was almost cracked apart, the crevices glowing with that same blue, unholy light. Blue-black wings stretched out behind it and a long, slender tail drug the ground. Horns were placed upon its head in a crown-like shape. 

“Rin, why does it have your flames?!” Izumo shouted, stepping back a couple of steps. “I thought you were the only one other than Satan with them!”

“Well, whatever it is, it’s about to get that sage!” Suguro exclaimed, swallowing his fear down. “I think we need to-”

“No, leave him alone.”

Suguro’s face fell, looking over to Rin, seeing tears pooling from the half-demon’s eyes, “Wait,  _ what _ ?”

Rin stepped forward in a zombie-like motion, tears streaming down his face, “What… Yukio, what the hell have you done?” he croaked. “What the hell did you do?”

“Wait,  _ Yukio _ ?” Konekomaru spun back around and studied the blue-black demon, its eyes now burning with that unholy blue fire, mainly from the left eye. “Rin, how… How is that your brother?”

“I… I don’t know….” Rin took another step forward. “Yukio, what did they do to you?” he asked. “Is this what you really wanted?”

Yukio remained motionless, watching Rin carefully with slitted eyes as the half-demon continued to walk towards him.  _ “Seems like Rin’s changed as well.”  _ Satan mused from inside the boy’s head, noting the white hair and the small horns that grew from his forehead  _ “But, you’re still the one that’s changed the most. You two are becoming more and more like my sons everyday.” _

“Yukio!” Rin shouted, running towards his changed brother. “What did you do?!”

“Piss off.” Yukio lashed out his scaled-covered arm, knocking Rin back. “Leave me alone, brother. You’re out of my league now. I… I’ve finally become  _ better  _ than you. Stronger. You may have changed, but I’m finally the one who has more power.”

“But at what cost, though?” Rin croaked, choking on a sob. Flames burned from his now-visible demon heart, illustrating his grief. “I don’t see my brother when I look at you, I just see a demon. And I thought that you hated demons. Why let the Illuminati do this to you? 

You know that they don’t care about you at all.” he continued. “There’s clearly something that they wanted out of this. They didn’t do it to make you more powerful just because that’s what you wanted. They made you into what they wanted you to be, whatever that is!”

Yukio’s eye flared, “Do you think that I care?” he asked, his gravelly voice rumbling. “‘Cause I don’t. You’re just in my way again. Like you always are.” His great wings bristled behind him, showing his frustration, “You’ll just screw things up again.”

Rin’s face fell, but he didn’t know what to say. How could he even find the words?

“Rin, we need to get the hell out of here!” Suguro yelled, keeping his distance. “That  _ thing  _ is not your brother, not anymore! I don’t know what the Illuminati did to him, but it clearly turned him into something else! Leave him be!”

“You better listen to your classmates.” Yukio rumbled, turning back to the sage and reaching out a clawed hand towards it. “I’m only here on a job, not for sentiment. You’re only getting in my way.”

Rin went to run towards his brother again, but stopped as he found Yukio hovering in the air with the sage between his claws, his wings stirring up a breeze. “Why are you working for them, Yukio?” he asked quietly. “The old man wouldn’t like it. Not at all.” He thought back to what he had seen in the past and even more tears began to fall.

“Do you really think that I care about that bastard? He only ever made things worse for me. Now run back to True Cross and try not to fuck anything else up.” Yukio snarled, starting to ascend higher into the air. He waved his free hand and a blast of blue flames shot out towards Rin, knocking the boy back once more.  _ “You’re more my son than he is, boy.”  _ Satan chided.  _ “I’m proud of you.”  _

“Shut up.”

Rin skidded across the grass, stirring up dirt as Yukio began to fly away. His stomach dropped as he sat up, his body shaking as he watched his brother disappear into the sky. 

“Rin!” Shiemi was suddenly back by his side, Nee in his lap. “Are you okay, he knocked you around a bit.”

Rin’s shoulders slumped, “No, I’m not.”

“I think we need to get back to the school.” Izumo said, coming up to them. “I don’t know what the hell just happened, but I don’t think it’s safe to stay here. We can figure something else out later. You-”

She was cut off as Rin slammed his fist into the ground, “Dammit!” he cried, tears staining the dirt underneath him. “I knew that he was stupid, but not  _ that  _ stupid! And he calls me reckless!”

“Rin,” Shiemi began, but she fell silent as she decided that trying to talk to him wasn’t the best course of action right now. Especially since more flames were starting to burn off of him. 

“He’s such an idiot.” Rin sobbed, leaning against the ground. Flames whipped off of him, growing in size as his anger and sadness towards his brother grew more and more. “Yukio…. Why?

You got the power you wanted, but at what cost?!”

**Author's Note:**

> So, this is my first AoEx fic! I know it's strange, but it's based on an idea that Yukio turns full-demon due to the Illuminati's experiments. (Kind of looks like Devilman.) I hope that you enjoyed!


End file.
